Red meat allergy may raise heart attack risk

You would think that one consolation of becoming allergic to red meat would be improved heart health. No such luck. A new study by the University of Virginia finds a possible link between an allergy to red meat and coronary artery disease.

“This novel finding from a small group of subjects from Virginia raises the intriguing possibility that allergy to red meat may be an under-recognized factor in heart disease,” study leader Coleen McNamara, MD, a professor of medicine at the UVA Cardiovascular Research Center, said in a statement. “These preliminary findings underscore the need for further clinical studies in larger populations from diverse geographic regions and additional laboratory work.”

The findings are of particular interest in the Southeast and Eastern U.S., where the lone star tick, whose bite can sensitize people to the red meat allergen, is most prevalent.

Funded by the National Heart, Lung, and Blood Institute (NHLBI), the Virginia scientists studied 118 patients who underwent intravascular ultrasound along with cardiac catheterization. They analyzed blood samples to screen for antibodies to alpha-Gal (galactose-α-1,3-galactose), a complex sugar that is the main allergen in red meat.

Alpha-Gal antibodies were found in blood samples from 26% of participants, and they had 30% more plaque buildup in their coronary arteries than those who weren’t sensitive to the allergen.

The association was most pronounced in those 65 years of age or younger and remained statistically significant after adjusting for possible confounders, such as diabetes, hypertension, and statin use. In addition, plaques in the arteries of participants sensitive to alpha-Gal tended to be less structurally stable, potentially increasing heart attack or stroke risk.

Scientists have long suspected that allergens can trigger immunological changes associated with plaque buildup, but this study is the first to identify a specific allergen, according to the NHLBI.

About Alpha-gal allergy

Researchers estimate that 1% of individuals in some regions might have a red meat allergy, although as many as 20% might develop alpha-Gal antibodies without allergy symptoms.

The Alpha-gal allergy, as it is formally known, causes a delayed reaction, occurring three to eight hours after eating mammalian meat products — beef, pork, bacon, veal, and other mammals, including apes and, of course, other humans. The reaction includes severe whole-body itching, swelling of the facial and mucous membranes, gastrointestinal upset and even anaphylaxis.

Those afflicted with the allergy don’t have to become vegetarians, as they are still able to eat fish and poultry.

There is some evidence that the allergy may recede over time although it’s reported that some patients have observed symptoms for 20 years or more.

The allergy to alpha-gal was first reported in 2009 by UVA researcher Dr. Thomas Platts-Mills, and his colleague Dr. Scott Commins. Since then, there have been increasing numbers of cases of the meat allergy reported across the U.S., especially as the lone star tick’s territory grows. Previously found predominantly in the Southeast, the tick has now spread west and north, all the way into Canada.

UVA’s new study suggests that doctors could develop a blood test to benefit people sensitive to the allergen. “This work raises the possibility that in the future a blood test could help predict individuals, even those without symptoms of red meat allergy, who might benefit from avoiding red meat. However, at the moment, red meat avoidance is only indicated for those with allergic symptoms,” said researcher Dr. Jeff Wilson of UVA’s allergy division.

The latest study was published in Arteriosclerosis, Thrombosis and Vascular Biology, a journal of the American Heart Association.

About the Author

Truman has been a bureau chief and correspondent in D.C., Los Angeles, Phoenix and elsewhere, reporting for radio, television, print and news services, for more than 30 years. Most recently, he has reported extensively on health and consumer issues for ConsumerAffairs.com and FairfaxNews.com.